Background: The genus mycobacterium includes several species that can cause disease.
Mycobacterium tuberculosis-complex is transmitted from person to person by air and usually
affects the lungs. Non-tuberculous mycobacteria (NTM) are transmitted from natural sources in
the environment and are often considered not a public health hazard. A number of mycobacterial
diseases occur due to close contacts between humans, domestic animals and the environment.
Objective: The objective of this study was to examine patients suspected of having
mycobacterial diseases and describe: 1) the association between mycobacterial diseases and
patient characteristics, 2) experienced risk factors, 3) knowledge and perceptions about TB in
agropastoral communities, and 4) at national level the investigation practices of retreatment cases
of mycobacterial disease in Tanzania.
Methods: Three studies were conducted to address the stated objectives. In order to identify risk
factors for mycobacteria, a cross-sectional study was conducted on 1711 patients examined for
tuberculosis (TB) (TB suspects). The suspects were enrolled from Mt. Meru Hospital (the Arusha
Regional Hospital), Enduleni Lutheran Hospital in Ngorongoro district, and Haydom Lutheran
Hospital in Mbulu district. The study areas were purposively selected because of their strong
human and animal habitat overlap. The participants were examined for mycobacteria by sputum
microscopy and culture at Central Tuberculosis Reference Laboratory in Dar es Salaam.
In a cross-sectional study, we selected 41 patients among the 277 confirmed mycobacteria
positive from the study mentioned above. Interviews were conducted to compare the patients
with 68 relatives and 55 neighbors about their perceived risk of exposure to mycobacteria and
knowledge about mycobacterial diseases. In a study on the national TB and laboratory registers,
we assessed the investigation practices for mycobacteria by reviewing of records of all TB
patients notified as re-treatment cases, and the number submitting their sputum samples for
culture and DST at the reference and three zonal laboratories between 2002 and 2010.
Results: We examined 1711 patients suspected of having TB of whom 927 (54.2%) were males.
Out of all the study participants, 277 (16%) were found to have sputum samples positive for
mycobacteria, 228 (13.3%) were smear positive and 123 (7.2%) were culture positive. Of the 123
mycobacterial culture positive, 15 (12.2%) had NTM. Of the 1711 study participants, 664 had
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known HIV sero-status, of whom 159 (23.9%) were HIV positive. Males were more likely than
females to have sputum samples positive for mycobacteria.